Background: To date the IMSI procedure represents the only real-time and unstained method available to discard spermatozoa with ultrastructural defects. Several studies demonstrated that IMSI provides positive results in couples with severe male factor infertility or repeated ICSI failures. Aim of this pilot study is to evaluate the differences between IMSI and ICSI in terms of IVF outcomes in an unselected infertile patient population.
Methods: Three hundred and thirty-two couples were analyzed: 281 couples underwent conventional ICSI procedure and 51 underwent IMSI technique.
Results: No statistically significant differences were found between implantation rate (ICSI: 16,83%; IMSI: 16,67%), fertilization rate (ICSI: 77,27%; IMSI: 80,00%) and pregnancy rate (ICSI: 25,30%; IMSI: 23,50%). Both groups were comparable when considering live birth rate (ICSI: 11,39%; IMSI:13,72%), ongoing pregnancy rate (ICSI: 7,47%; IMSI: 5,88%) and miscarriage rate (ICSI: 17,78; IMSI: 5,26%). The subgroup analyses did not show a statistical difference between ICSI and IMSI neither in male factor infertility subgroup nor in patients with more than one previous ICSI attempt. A trend towards better laboratory and clinical outcomes was detected in the male factor infertility subgroup when IMSI was applied.
Conclusions: Our preliminary results show that the IMSI technique does not significantly improve IVF outcomes in an unselected infertile population.